I have been running into a lot of video files with very low volume lately. It has made it a little difficult to watch them on my TV after I copy them over. I am looking to increase the volume to a uniform level.

Can anyone recommend a meter to measure the audio volume of AVI, FLV & MP4 type files? I am presently using Gom Player to view these files on my PC.

If you want this done automatically, the word to look for is normalise/normalize. This can typically be done in one of two ways and you'll have to choose which one works best for you: re-encode the files at higher volume settings, or get a player that does it for you during playback.

Thanks for the replies. I'm aware of 'normalize'. I've been using a program that enables me to adjust the volume on a video file.

What I'm looking for is a meter that shows/measures the current volume to assist me in deciding how much I should raise it. The meter could be in the forms of bars showing the amount of decibels or two audio meters. I've tried Windows VU Meter, but it doesn't seem to work.

then sox is compiled with the ffmpeg library it can analyze video files,...

Code:

sox "Path to file" -n stat

Problem is you will probably have to compile it yourself, since as far as I remember the normal sox versions come without the ffmpeg library included,... (you could decode with e.g. ffmpeg and pipe the output to sox for analysis)

Problem with doing it that way is the potential for unintended clipping, plus unless you are a seasoned audio guy you won't be able to match RMS via waveform and meters as most softs are instantaneous peak meters, which Normalization already does for you automatically. That brings about the whole question about "what is considered an even level?" (when given a wide variety of sounds/instruments/dynamics).

Just a guess: are most of your "low audio" files using AC-3? AC-3 uses DialNorm to even the "overall volume levels" of the programs out, but they are often specifically encoded at a lower level, so that might account for what you are experiencing.

Try running ReplayGain on the audio. It works pretty well for stereo tracks but I haven't used it on multichannel audio myself.

Most programs capable of ReplayGain scanning are designed to scan music files and base the result on a "target volume" of 89db. Ideally you'd probably want to use 83db or 84db for video soundtrack audio as it tends to have a little more dynamic range than "music" tracks. The ReplayGain scan result should also tell you if the peaks are greater than 0db (lossy audio can contain peaks above 0db so while they're louder they're not actually clipped in the audio file itself). It'll also tell you if adjusting the volume according to the ReplayGain result will cause "clipping". A few db of "clipping" is no big deal though.... the peaks are above 0db using lossy audio but as I said they're not actually "clipped".

Anyway.... once you've run a ReplayGain scan on the audio you'll probably need to re-encode it while adjusting the volume accordingly. The ReplayGain info can also be saved to tags in the audio/video files and in theory the player should read them and adjust the volume on playback so there's no need to re-encode it, but unfortunately I don't know of any video players which support ReplayGain tags. Some software players might, but I'd be astounded if any hardware players do.

If I'm going to run a ReplayGain scan I generally do it using foobar2000. It's an audio player/converter but it'll also play the audio inside common video containers (MKV/MP4/AVI etc). If it can save the ReplayGain info to tags, you can set up foobar2000's converter to use the info when re-encoding and it'll automatically adjust the volume as it encodes.

The one exception to the "re-encoding" rule is MP3 audio. It's the only audio format which can have it's audio changed without needing to re-encode. Foobar2000 can change MP3 volume losslessly but you'll need to extract it from the video files first. MP3Gain is also a handy program to have for adjusting MP3 volume without re-encoding. I use it on all my MP3s before transferring them to my MP3 player.

The methods mentioned above are all good, but I have run into problems where Media monkey , audacity, etc when measuring volume of the audio portion of some VIDEO files. I use a manual method that unfortunately needs to have each video tested separately, at least a portion of it but This is not much of a problem for me since I just test the next file while another is converting.

Bear in mind that the level displayed also depends on what your volume level is set to, but then again, I am trying to adjust the level to MY needs so it too is not a problem. I just set my player to mid scale and Windows audio to 35. If the sound is low, then I just note the reading on the meter and adjust accordingly.

This level meter also adjusts for 0 decibel level corresponding to the gauge and has a marker that you can set to freeze at peak audio or allow the marker to reset after a delay which is very handy to measure peak volume. The nice thing about this meter is that is measures the active level of the sound card and does not need a microphone like some.

This method may be a little slow if you are looking for a large batch conversion process but your problem sounded similar to one I had when converting a few videos at a time or creating a DVD and it worked well for me.